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More on Houston’s transit deserts

James Llamas writes a guest post at the Kinder Institute blog about their earlier article on transit deserts in Houston.

HoustonMetro

As a planner at Traffic Engineers, Inc. I had the privilege of working with METRO staff and industry experts on the reimagining plan. The project has received quite a bit of attention around the country, and it’s encouraging to have well-respected researchers evaluating its effectiveness in different ways. Coincidentally, Reimagining was assailed early on by critics who alleged it would create “transit deserts,” presumably large areas with no transit service whatsoever. As it turned out, we were able to maintain service within a half mile of over 99.95 percent of existing riders (their boarding location, at least, which is all we actually know), including most of those in very low-ridership and hard-to-reach locations.

The notion that transit riders in large swaths of the city will be left high and dry is demonstrably false, and, of course, the vast majority of riders will see significantly improved service.

[…]

Reading through the study, the assumption on bus stops presents the first problem.

“Since information on the location of transit stops is not available yet,” the authors say, “points were placed along the future routes roughly every quarter mile and multiplied times two to account for a stop on either side of the road.”

Is this reasonable? In fact, all existing bus stops will be retained unless the street in front of them will no longer have service in the new network. This is a fate that will befall only a handful of stops each in Sharpstown and Gulfton, mostly located on end-of-line loops that will no longer exist. Practically all stops along major streets will remain.

So is the quarter mile spacing an accurate assumption? As many a weary bus rider can tell you, METRO local buses tend to stop much more often than that. The mile of Bellaire Boulevard centered on the intersection with Fondren Road in Sharpstown has seven bus stops in each direction. If the researchers placed four stops in each direction along this mile, they incorrectly assumed a 40 percent reduction in the number of stops. The typical spacing of stops along METRO’s local routes is more like one-sixth to one-fifth of a mile, so the quarter-mile assumption would provide a significant undercount. This likely explains part of the supply reduction alleged by the study.

But, perhaps more significantly, is the number of bus stops even a good measure of transit service quality? Most people on a bus stopping six times each mile would say no. Certainly, a base number of stops need to exist to allow people along the route to access the bus, but after a certain point (about quarter-mile spacing) adding stops has diminishing returns. According to the assumptions underlying the study, however, adding more stops is always better. This is an aspect of the methodology that should be reevaluated.

[…]

If the metrics used in the UT study could lead to incorrect conclusions about transit service supply, what measures should be used instead? I would suggest that weekday bus trips be replaced by total weekly bus trips since most people – even we transit riders – have places to go on the weekends. Inadequate weekend service is a great way to force people into car ownership who would rather do other things with their household budget.

We saw how basing the index on the gross number of routes could be problematic. At the same time, number of routes can be an indicator of the number of destinations reachable from a particular area. Perhaps double-counting routes that meet a certain frequency threshold like 15 minutes would yield more accurate results.

All of this isn’t to say that the parts of town called out in the study can’t use more transit service. They undeniably can. The methods developed by Nichols and Jiao hold great promise in helping transit planners identify areas where improved service is most needed. For instance, on this basis the 32 Renwick/San Felipe should be prioritized for a frequency increase when the budget allows.

See here for the study and here for the Kinder Institute post about it. I had my own critiques of the study, but I do agree with Llamas that it was a valuable idea that will help guide the discussion going forward. I don’t have anything to add to Llamas’ article, I just wanted to note what he said and to say again that I hope the study authors consider the feedback they have received and take another crack at it soon.

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